package com.sari.common.utils;

import java.io.UnsupportedEncodingException;

/**
 *
 * 转换字符串的编码
 * Created by WANGSF on 2015/3/24.
 */
public class CharsetUtils {
    /** 7位ASCII字符，也叫作ISO646-US、Unicode字符集的基本拉丁块 */
    private static final String US_ASCII = "US-ASCII";

    /** ISO 拉丁字母表 No.1，也叫作 ISO-LATIN-1 */
    private static final String ISO_8859_1 = "ISO-8859-1";

    /** 8 位 UCS 转换格式 */
    private static final String UTF_8 = "UTF-8";

    /** 16 位 UCS 转换格式，Big Endian（最低地址存放高位字节）字节顺序 */
    private static final String UTF_16BE = "UTF-16BE";

    /** 16 位 UCS 转换格式，Little-endian（最高地址存放低位字节）字节顺序 */
    private static final String UTF_16LE = "UTF-16LE";

    /** 16 位 UCS 转换格式，字节顺序由可选的字节顺序标记来标识 */
    private static final String UTF_16 = "UTF-16";

    /** 中文超大字符集 */
    private static final String GBK = "GBK";

    /**
     * 将字符编码转换成US-ASCII码
     */
    public static String toASCII(String str) throws UnsupportedEncodingException {
        return changeCharset(str, US_ASCII);
    }
    /**
     * 将字符编码转换成ISO-8859-1码
     */
    public static String toISO_8859_1(String str) throws UnsupportedEncodingException{
        return changeCharset(str, ISO_8859_1);
    }
    /**
     * 将字符编码转换成UTF-8码
     */
    public static String toUTF_8(String str) throws UnsupportedEncodingException{
        return changeCharset(str, UTF_8);
    }
    /**
     * 将字符编码转换成UTF-16BE码
     */
    public static String toUTF_16BE(String str) throws UnsupportedEncodingException{
        return changeCharset(str, UTF_16BE);
    }
    /**
     * 将字符编码转换成UTF-16LE码
     */
    public static String toUTF_16LE(String str) throws UnsupportedEncodingException{
        return changeCharset(str, UTF_16LE);
    }
    /**
     * 将字符编码转换成UTF-16码
     */
    public static String toUTF_16(String str) throws UnsupportedEncodingException{
        return changeCharset(str, UTF_16);
    }
    /**
     * 将字符编码转换成GBK码
     */
    public static String toGBK(String str) throws UnsupportedEncodingException{
        return changeCharset(str, GBK);
    }

    /**
     * 字符串编码转换的实现方法
     * @param str  待转换编码的字符串
     * @param newCharset 目标编码
     * @return
     * @throws UnsupportedEncodingException
     */
    public static String changeCharset(String str, String newCharset)
            throws UnsupportedEncodingException {
        if (str != null) {
            //用默认字符编码解码字符串。
            byte[] bs = str.getBytes();
            //用新的字符编码生成字符串
            return new String(bs, newCharset);
        }
        return null;
    }
    /**
     * 字符串编码转换的实现方法
     * @param str  待转换编码的字符串
     * @param oldCharset 原编码
     * @param newCharset 目标编码
     * @return
     * @throws UnsupportedEncodingException
     */
    public static String changeCharset(String str, String oldCharset, String newCharset)
            throws UnsupportedEncodingException {
        if (str != null) {
            //用旧的字符编码解码字符串。解码可能会出现异常。
            byte[] bs = str.getBytes(oldCharset);
            //用新的字符编码生成字符串
            return new String(bs, newCharset);
        }
        return null;
    }


    public static String encodeUnicode(String str){
        char[]arChar=str.toCharArray();
        int iValue=0;
        String uStr="";
        for(int i=0;i<arChar.length;i++){
            iValue=(int)str.charAt(i);
            if(iValue<=256){
                // uStr+="& "+Integer.toHexString(iValue)+";";
                uStr+="\\u00"+Integer.toHexString(iValue);
            }else{
                // uStr+="&#x"+Integer.toHexString(iValue)+";";
                uStr+="\\u"+Integer.toHexString(iValue);
            }
        }
        return uStr;
    }

    public static String decodeUnicode(String theString) {
        char aChar;
        int len = theString.length();
        StringBuffer outBuffer = new StringBuffer(len);
        for (int x = 0; x < len;) {
            aChar = theString.charAt(x++);
            if (aChar == '\\') {
                aChar = theString.charAt(x++);
                if (aChar == 'u') {
                    // Read the xxxx
                    int value = 0;
                    for (int i = 0; i < 4; i++) {
                        aChar = theString.charAt(x++);
                        switch (aChar) {
                            case '0':
                            case '1':
                            case '2':
                            case '3':
                            case '4':
                            case '5':
                            case '6':
                            case '7':
                            case '8':
                            case '9':
                                value = (value << 4) + aChar - '0';
                                break;
                            case 'a':
                            case 'b':
                            case 'c':
                            case 'd':
                            case 'e':
                            case 'f':
                                value = (value << 4) + 10 + aChar - 'a';
                                break;
                            case 'A':
                            case 'B':
                            case 'C':
                            case 'D':
                            case 'E':
                            case 'F':
                                value = (value << 4) + 10 + aChar - 'A';
                                break;
                            default:
                                throw new IllegalArgumentException(
                                        "Malformed   \\uxxxx   encoding.");
                        }
                    }
                    outBuffer.append((char) value);
                } else {
                    if (aChar == 't')
                        aChar = '\t';
                    else if (aChar == 'r')
                        aChar = '\r';
                    else if (aChar == 'n')
                        aChar = '\n';
                    else if (aChar == 'f')
                        aChar = '\f';
                    outBuffer.append(aChar);
                }
            } else
                outBuffer.append(aChar);
        }
        return outBuffer.toString();
    }

    public static void main(String[] args) throws UnsupportedEncodingException {
//        CharsetUtils test = new CharsetUtils();
        String str = "FT\uD83C\uDF3B心";
//        System.out.println("str: " + str);
//        String gbk = test.toGBK(str);
//        System.out.println("转换成GBK码: " + gbk);
//        System.out.println();
//        String ascii = test.toASCII(str);
//        System.out.println("转换成US-ASCII码: " + ascii);
//        gbk = test.changeCharset(ascii,CharsetUtils.US_ASCII, CharsetUtils.GBK);
//        System.out.println("再把ASCII码的字符串转换成GBK码: " + gbk);
//        System.out.println();
//        String iso88591 = test.toISO_8859_1(str);
//        System.out.println("转换成ISO-8859-1码: " + iso88591);
//        gbk = test.changeCharset(iso88591,CharsetUtils.ISO_8859_1, CharsetUtils.GBK);
//        System.out.println("再把ISO-8859-1码的字符串转换成GBK码: " + gbk);
//        System.out.println();
//        String utf8 = test.toUTF_8(str);
//        System.out.println("转换成UTF-8码: " + utf8);
//        gbk = test.changeCharset(utf8,CharsetUtils.UTF_8, CharsetUtils.GBK);
//        System.out.println("再把UTF-8码的字符串转换成GBK码: " + gbk);
//        System.out.println();
//        String utf16be = test.toUTF_16BE(str);
//        System.out.println("转换成UTF-16BE码:" + utf16be);
//        gbk = test.changeCharset(utf16be,CharsetUtils.UTF_16BE, CharsetUtils.GBK);
//        System.out.println("再把UTF-16BE码的字符串转换成GBK码: " + gbk);
//        System.out.println();
//        String utf16le = test.toUTF_16LE(str);
//        System.out.println("转换成UTF-16LE码:" + utf16le);
//        gbk = test.changeCharset(utf16le,CharsetUtils.UTF_16LE, CharsetUtils.GBK);
//        System.out.println("再把UTF-16LE码的字符串转换成GBK码: " + gbk);
//        System.out.println();
//        String utf16 = test.toUTF_16(str);
//        System.out.println("转换成UTF-16码:" + utf16);
//        gbk = test.changeCharset(utf16,CharsetUtils.UTF_8);
//        System.out.println("再把UTF-16码的字符串转换成UTF_8码: " + gbk);
//        String s = new String("中文".getBytes("UTF-8"),"UTF-8");
//        System.out.println(s);
//        String unicode = toUnicode(str);
//        System.out.println(unicode);
//        System.out.println(decodeUnicode(unicode));
//        byte[] utf16 = test.getBytes("UTF-16");
//        System.out.println(toHex(utf16));
    }
}
